textproduct: Albany

WHAT HAS CHANGED

No significant changes were made to the forecast with this update given the persistence of a relatively quiet weather pattern.

KEY MESSAGES

1) Low probabilities for even minor impacts as a result of snow showers Friday afternoon into Saturday.

2) Moderate to high confidence in another period of dangerously cold temperatures this weekend into early next week.

DISCUSSION

KEY MESSAGE 1...

A clipper surface low system will track eastward, closely along the international border to our north, Friday afternoon into Saturday. Aloft, the associated closed cyclone will remain much farther to our north, extending a fairly potent shortwave trough southward into our region about its southern periphery. With the slight deepening of both the closed low aloft and surface cyclone, a fairly steep axis of cyclonic vorticity advection will develop as the shortwave rotates through the region. Despite the enhancement to ascent both in the low- and upper- levels, this will be a rather moisture-starved and progressive system. Therefore, while our next best chance for widespread precipitation can be attributed to this clipper, much of the snow we see will be very light to potentially locally moderate in nature where orographic lifting mechanisms across some of our higher terrain regions can also enhance snowfall.

There are also some hints in the mid- to long-range guidance for a band of mid- to low-level FGEN developing across portions of the region Friday night and/or early Saturday morning. During this same time, the low is anticipated to depart from overhead to the east, allowing a steepening pressure gradient to develop as high pressure builds quickly in its wake over the Great Lakes. And, with forecast soundings indicating a saturated DGZ, there is certainly potential for some stronger snow showers to even snow squalls early Saturday morning along the passage of the potent cold front associated with the clipper low. Still, these would not impact snowfall amounts greatly and being that their occurrence would be early on a weekend day, there luckily wouldn't be much of a societal impact either. In fact, the Weather Prediction Center Probabilistic Winter Storm Severity Index indicates low probabilities (5-20%) for even minor impacts (a few inconveniences to daily life due to winter driving conditions) across the region Friday afternoon into Saturday afternoon from the whole of this system.

KEY MESSAGE 2...

Our days of temperature moderation unfortunately are numbered as another period of dangerously cold conditions is becoming increasingly likely for this weekend. In the wake of the cold front of the aforementioned system, another shot of arctic air will envelope eastern New York and western New England. According to the latest NAEFs, both 700hPa and 850 hPa temperatures will range between 1.5 to nearly 2.5 STDEVs below normal from Friday night through Monday. This will translate to surface temperatures that range from about 2 to 2.5 STDEVs below normal beginning Saturday and lasting through Monday as well.

To make matters feel worse, a lingering cold advection regime behind the front as well as a steepened pressure gradient, especially Saturday, will elevate wind gusts. So, not only will air temperatures be very cold, but wind chill values, or "feels-like" temperatures, will become dangerously cold regionwide. And while winds begin to decrease Sunday and into Monday as high pressure regains control, breezy conditions will continue to make for dangerous wind chills through at least Sunday night and possibly even Monday. At this time, the latest NBM Minimum Temperature QMD probabilities for <1F are about 20 to 90% for Friday night, 40-100% for Saturday night; and 30-100% for Sunday night. Should the NBM maximum wind gust forecast for these time periods verify, wind chill values will be in the 10s to 20s and potentially even 30s below zero. We will continue to monitor trends over the coming days to nail down the exact wind chill forecast. However, know that Cold Weather Advisories and potentially Extreme Cold Watches/Warnings will likely be needed in the near future.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

Through 00Z Wednesday...VFR conditions at all terminals as of 6:20 PM should prevail through at least midnight. However, multiple sources of guidance continue to suggest the possibility for trapped low-level moisture to result in low stratus with IFR to LIFR cigs and possibly vsbys developing after around 06z. Low confidence on exact timing, so have added temp groups to give a window for approximate timing on cigs developing. Best chance is at ALB/GFL/POU as winds will be slightly stronger at PSF, but will continue mention there too from the previous TAF. Low stratus likely persists through 13-15z before beginning to mix out, with SCT to BKN clouds 1500-2500 ft through around noon as the stratus deck lifts. Expecting a trend back to VFR conditions tomorrow afternoon, but will see increasing mid-level cloud cover ahead of a weak upper-level disturbance approaching from the west tomorrow evening. Winds will be light and variable at GFL/POU through tomorrow afternoon before increasing to 3-6 kt from the S/SE. At ALB/PSF, 4-8 kt winds from the W/NW diminish to 5 kt or less after 06z, and increase to around 5 kt again from the S/SE as well late tomorrow morning or early afternoon, continuing through the end of the TAF period.

Outlook...

Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: No Operational Impact. NO SIG WX. Wednesday Night: No Operational Impact. NO SIG WX. Thursday: No Operational Impact. NO SIG WX. Thursday Night: No Operational Impact. NO SIG WX. Friday: Moderate Operational Impact. Chance of SHSN. Friday Night: Moderate Operational Impact. Breezy. Chance of SHSN. Saturday: Low Operational Impact. Breezy. NO SIG WX.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.